Crap, I just broke my Foreplay

BlackSwamp

Previously DingusBoy
Did the anticipation upgrade on my Foreplay and one of the boards (four total) isn't working. I traced the voltages so I know it's in the board (not miswired somewhere in the Foreplay) but I don't know what it could be.

There are two LEDs that are supposed to light but don't and the voltage coming out is way too high. I looked at the solder joints and they look good and compared it to the identical board on the other channel and everything is in it's place. Only thing I can think of is I put an LED in backwards but I thought I double checked them.

CRAP!
 
Ding...


If you haven't already, go post at the BottleHead Forum. I know you already know how good they are. But go use them.

While your waiting for some answers. Reread the Anticipation constant current source upgrade instructions. Double check the wiring while your going thru the instruction again.

It seems there has to be something mixed up somewhere. You'll have music soon enough.
 
Well, I have double checked the connections, voltage and such against the working unit on the other channel and I can't figure out what is up with this thing.

I checked the transistors, they are installed correctly and the diode test seems to indicate they are ok. In circuit they test the same as the working unit.

Same with the LED's, diode test implies they are installed correctly as the values are consistent with the working unit. In circuit I get values one way but not the other.

I need to post on the bottlehead forum -I've been out for awhile and just got home- but my limited troubleshooting skills tell me this should be working.

I go back to my original statement, CRAP!
 
I know this will sound stupid, but did you make sure you soldered all the pins on the board?
 
I'm not sure if these will be clear enough to reveal anything but here are pics of front and back.

Solder side:
 
After reviewing the Bottlehead forum and checking voltage with the stock resistor as opposed to the troublesome board, my next attempt will be to fix any potential cold solder joints. They don't look cold but Doc says that is the problem 98% of the time.

It's reassuring (and really narrows things down) to know it checks out with the stock resistor. One small board with 6 components on it shouldn't be too bad.

Wish me luck.
 
Good luck man! get that thing goin!

when i had mine built and was testing it i thought id blew it for sure a couple of times


First was when i turned it on for the first time. ive got it upside down on a couple 2x4's looking at the tubes.. c'mon. c'mon wheres the glow? ok well at this point im ready to stick my hands in a live amp so i have every light on within a 5 mile radius so i think. well maybe its just too bright. turn the lights off. flip the switch on the power strip i use to do this sort of thing and nothing! wtf ok now im getting worried. my fuse isint blown and i have no glow.

DOH !! the power switch on the amp! it must be in the off position! flip the switch on the amp, flip the switch on the power strip, say a couple of prayers and HA we have glowing filaments!

now comes the worst part. I test it all out and everything is just great. Now its hooked up to my halfway fixed Au517,and some old bose interaudio 1000's with no woofer surrounds and our dvdp, ok now ive got the sweet whispers and before i hooked it all up i measured the resistance on them, i figured that the position measuing the most resistance will be the low volume position. assuming this i pop in a cd that i know has a track that starts out kinda soft, just to be sure. well it plays and i can hear it. barely.. i turn the volume knobs every which way and it doesnt change.. ok this cant be good. DOH!! you got the selector switch on the wrong input dummy!

ok fixed that problem. discovered there is some leakage in the selector switch though but its pretty un noticable so all is well.

Back to playing music. now ive got it ready to go, got my hand on the speaker selector knob on the sansui *just incase* thank god i did, i Sloowly start turning the knob BAM!!!!!!!! holy shi* bout near blew whats left of the speakers out! full volume! lol.

DOH!! i measured the resitance on the stock post, Ooohh. the lowest resistance is the low setting. Now ya tell me! Finally i get it working. Ahh. if something didnt go wrong i might have been worried! :D

And that folks concludes my DOH!! diy story for this project.
 
For those who care, I posted this over at the Bottlehead forum this morning:

Hi all,
I could use some feedback on a problem I'm having with one VA board.

I built the Foreplay stock some time ago and built the anticipation boards this weekend. I installed and powered up the amp and am having a problem with 1 VA board. The two CF boards and other VA board are working fine.

Problem: No lights on either of the LED's and lead B (going to the plate) reads voltage of around 150 as opposed to the desired 50v's. Voltage inside the board matches the working VA board except at the collector of the MJE350 which is connected to lead B.

Troublshooting thus far:

Quadruple check all connections to make sure they are correct as related to instructions and working VA board. They are.

Diode tested LED's: They test the same as the working board. Values one way but not the other.

Diode tested Transistors: Same as LED's, values match good board in every possible configuration. Two readings and the others have no values as I understand transistors should.

Confirmed resistance of resistors with ohmmeter.

Tested voltages on Foreplay with stock resistor in circuit as oppossed to the VA board in question and all voltages test as they should. So, my assumption here is the problem must be in the board and not in an error in connecting it to the Foreplay.

I've reviewed some of the past links on anticipation upgrades here and the only thing mentioned there that I have yet to tackle is the possibility of cold solder joints. Could that be it? They look good.

Thanks in advance,

Brad
 
Ding...Any update?


How were the solder joints?


I seen the thread at bottlehead...but I couldn't tell if you fixed it yet. If it still isn't working...did all the resistance and voltage checks check out? Have you tried to swap the boards that aren't working?

Hmmm...again...what is or isn't working on the foreplay.


good luck!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
Hey GF,

Thanks for asking, I've done everything suggested but swap the boards. If it works, I'll be confused but my delay is I just haven't had the time.


I reheated the solder joints even though they looked good. I also took the original resistor and put it in to check voltages and everything checked. I had it running with three boards and resistor and it seemed to pass a quick ear check as well.
 
Day after the fest, Echowars and I had a chance to look into it. turns out one of the LEDs were bad. Went to Ratshack and picked up a replacement and got some helpful hints on soldering/desoldering from Echo as we replaced it.

Back in business and sounding good. :grnbounce
 
so how much better is the sound after doing the upgrade? after not having it up and running for soo long you probbly cant do a real comparison but surely if its as good as people say you can hear it. right?
 
I will give a report in a day or two. Echowars & I listened to some tunes this evening and it sounded really good but we were working on some other things and talking at the same time. Until I can sit down by myself and spin a few albums I really can't say.
 
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